In some temporal log structured database systems, maintaining current information may not be sufficient; rather historical data must be maintained to handle relevant queries. The underlying access method of such systems should support different forms of “time-travel” queries, large keys, high insertion rates and retrieval rates, and should be able to manage a large volume of data with an efficient use of storage media. Indexing temporal databases can be an important and challenging problem, due to the large amount of data to be indexed and the various “time-travel” types of queries that have to be supported.
An important and desirable feature for a temporal database system can be the ability to sustain high insertion rates. Such a requirement can arise, for example, in transaction monitors that are fed by transaction processing systems such as, for example, the CICS (“Customer Information Control System”) transactional server or the IBM DB2 relational model database. For example, a transaction management system can retain each unit of recovery across various z/OS subsystems in order to provide a correlated view of the entire business transaction across the diverse z/OS subsystems. In addition to querying within the database system, a current unit of recovery, queries asking for the history of a specific unit of recovery in a given time interval, as well as queries asking correlated view of units of recovery can be supported. The results of these queries can be important for performance studies and source problem isolation.
Typically, the amount of data records to be inserted into such transactional databases is much greater than the amount of data records actually retrieved from the database at a later time. Thus, it is desirable to optimize the insertion process without being detrimental to the retrieval process.
Thus, a need exists for an access system and method for transaction-time temporal data that can meet the above-described demands of such a transaction management system and can optimize the insertion process.